1. Technical Field
The present invention relates to a wiring method for a head suspension assembly in which a tab frame formed integrally with a suspension is used, and a head suspension assembly stand used in the wiring method, and a flexure assembly, a suspension assembly, and a wiring method for the head suspension assembly.
2. Description of the Related Art
In hard disk drives (HDD), by moving magnetic read and write heads in substantially the radial direction of a rotating magnetic disk, data at any location on the magnetic head is accessed. A head suspension assembly (HSA) is a member which has the magnetic heads and moves over the magnetic disk. The HSA is attached to a shaft having an axis of rotation orthogonal to the recording surface of the magnetic disk through an actuator arm or directly, and rotates on a plane parallel with the recording surface of the magnetic disk. This allows the magnetic read and write heads mounted on the top portion of the HSA to move in substantially the radial direction of the magnetic disk. The HGA typically comprises a suspension assembly, a slider, and a lead assembly.
The slider is provided with the magnetic read and write heads, and a connection pad portion to which the lead wires of these magnetic heads are connected. To the connecting pad portion, a plurality of leads are connected. The plurality of leads connect the magnetic read and write heads and a controller which transmits data between the magnetic heads. The lead assembly binds the leads in an insulated state.
The leads are arranged in the longitudinal direction of the suspension assembly. One end of the leads is electrically connected to the magnetic heads through the connecting pad portion of the slider. The other end of the leads is electrically connected to the controller. Specifically, the one in which the leads are formed of wires and these plurality of wires are insulatively sheathed by a tube of polyurethane resin or the like and collected is called a wire assembly.
In the suspension assembly, a base plate, a load beam and a flexure are integrally constructed. The base plate has an attaching portion which is attached to the actuator arm or the shaft. The load beam is spot welded to the base plate, for instance, in a plurality of positions. The flexure is provided on the top portion of the load beam, and it is bonded to the load beam by a bonding agent or spot welding. The slider is fixed to the flexure.
When the magnetic disk rotates, air enters between the magnetic disk and the slider to form a so-called air bearing. The air bearing allows the slider to rise in proximity of the disk surface. The load beam gives the slider a resilient force (spring force) against the lift (levitation force) of the slider. The flexure gives the slider riding on the air bearing flexibility accommodating the very small recesses and protrusions on the disk surface. This allows the disk and the slider to be close to each other without contacting them, so that the distance between them is kept substantially constant.
A combination of the load beam and the flexure is called a suspension in the sense that the combination elastically supports the slider. An arrangement obtained by adding the base plate or the like to the suspension is called a suspension assembly, and an arrangement obtained by attaching the slider to the suspension assembly and wiring leads is called a head suspension assembly (HSA).
As a method for arranging a plurality of wires on the suspension assembly and connecting the wires and the connecting pads on the slider, a method of assembling HSA using a tab frame formed integrally with the suspension is disclosed, for instance, in the specification of Japanese Published and Unexamined Patent Application No. 9-128726.
A conventional method of assembling HSA""s is shown in FIGS. 20 and 21. FIG. 20 is a top view of the top portion of the suspension assembly. Further, FIG. 21 is a side view of the top portion of the suspension assembly shown in FIG. 20; FIG. 21(a) is a side view only of the load beam, FIG. 21(b) is a side view only of the flexure assembly, and FIG. 21(c) a side view of the suspension assembly integrating them.
A suspension assembly 1 is configured by integrally stacking a load beam 10 shown in FIG. 21(a) and a flexure assembly 20 shown in FIG. 21(b). The suspension assembly 1 is supported by first support means, not shown, on which the suspension assembly 1 can be removably mounted. The load beam 10 is formed from sheet-like stainless steel having a thickness of several tens of mm. As shown in FIGS. 20 and 21, the load beam 10 comprises a plane portion 10a which narrows in the width toward the top end thereof, ribs 11 and 12 provided on the side edge portions on both sides of the plane portion 10a, and a merge lip 15 forming the topmost portion of the load beam 10.
The ribs 11 and 12 are provided to ensure the rigidity of the load beam 10. The plane portion 10a is provided with a plurality of holes 16a, 16b, 16c, 16d, 16e, and 16f, which are used to make the load beam 10 lightweight as well as for positioning in the assembling of the HSA. It is required that the HSA should be lightweight and have certain rigidity to perform its rotary motion at high speed. The HSA is exposed to the air flow generated by the rotating disk. This air flow deforms and vibrates the HSA. The load beam 10 is required to have rigidity resisting the deformation force.
Further, in the top portion of the plane portion 10a (rear side of the merge lip 15), there is provided an opening window 13 for connecting four wires 40 to the corresponding bonding pads 51 on a slider 50, respectively. On the central axis (not shown) of the suspension assembly (load beam 10) on the rear side of the opening window 13, there is provided a gimbal pivot 14 extending downwards in the figure.
The flexure assembly 20 is formed from a sheet of stainless steel which is thinner than the load beam 10. As shown in FIGS. 20 and 21, the flexure assembly 20 has a flexure 21 and a tab frame 30, which is configured integrally with the flexure 21. The rear side of the flexure 21 is integrated with the load beam 10 by bonding or spot welding. On the top side of the flexure 21, there is provided a suspension tongue 22 abutting on the gimbal pivot 14 of the load beam 10. The suspension tongue 22 is one-point supported by the gimbal pivot 14 of the load beam 10. A slider 50 is bonded to the suspension tongue 22 in a later step. The slider 50 is one-point supported by the gimbal pivot 14 through the suspension tongue 22, so that it can slightly incline in any direction. The HSA having such gimbal mechanism is particularly called a head gimbal assembly (HGA: Head Gimbal Assembly).
The tab frame 30 is configured by an A-side frame 31, a B-side frame 32, and a C-side frame 33 which are arranged so as to surround the periphery of the top side of the load beam 10. The A-side frame 31 and the B-side frame 32 are connected to the flexure 21. The A-side frame 31 and the B-side frame 32 are provided symmetrically with respect to the central axis of suspension assembly 1, and they are extending in substantially parallel with the central axis of the suspension assembly 1, respectively. The C-side frame 33 is connected to the A-side frame 31 and the B-side frame 32 in the top side of the suspension assembly 1.
The A-side frame 31 is connected to the flexure 21 by its connecting portions 31a and 31b. A cutout hole 31c is provided between the connecting portions 31a and 31b. The A-side frame 31 is connected to the C-side frame 33 by its connecting portions 31d and 31e. A cutout hole 31f is provided between the connecting portions 31d and 31e. 
Similarly, the B-side frame 32 is connected to the flexure 21 by its connecting portions 32a and 32b. A cutout hole 32c is provided between the connecting portions 32a and 32b. The B-side frame 32 is connected to the C-side frame 33 by its connecting portions 32d and 32e. A cutout hole 32f is provided between the connecting portions 32d and 32e. These cutout holes 31c, 31f, 32c, and 32f are provided to ease the separation of the tab frame 30 from the flexure 21 in a later step.
The C-side frame 33 crosses the merge lip 15 of the load beam 10, and it comprises a first plane portion 33a to which the A-side frame 31 and the B-side frame 32 are connected, a step portion 33b which forms a step in the right side edge portion of the first plane portion 33a in the drawing, and a second plane portion 33c extending through the step portion 33b to the right of the first plane portion 33a in the drawing. The first plane portion 33a is provided so as to be substantially coplanar with the plane portion 10a of the load beam 10. On the other hand, the second plane portion 33c is provided so as to be substantially coplanar with the merge lip 15 of the load beam 10.
The four wires 40 in a tube, not shown, are attached to the rear side of the suspension assembly 1. Each wire 40 is fixed on a predetermined location on the load beam 10 by a bonding agent 41, while being led from the rear side to the top side of the suspension assembly 1. At the rear side of the load beam 10, not shown, the four wires 40 are divided into two on both sides of the load beam 10, two wires for each side, and led to the top side of the load beam 10. The wires 40 divided for both sides further cross the opening window 13 of the load beam 10, intersect each other on the merge lip 15, are led to a predetermined location on the second plane portion 33c of the C-side frame 33, and fixed by a bonding agent.
The slider 50 is vertically raised in the drawing, as shown is FIG. 21(c), and arranged so that part of it passes through the opening window 13 of the load beam 10. The slider 50 is supported by second support means, not shown, for removably mounting the slider 50. On the upper surface of the slider 50, four bonding pads 51 are placed in parallel, as shown in FIG. 20.
When each of the four wires 40 is bonded to a predetermined location on the second plane portion 33c of the C-side frame 33, it is positioned so as to be put in contact with or close to the corresponding bonding pad 51 on the slider 50. Each wire is connected to each bonding pad 51 by ultrasonic welding, as known well.
When each wire 40 is connected to each bonding pad 51 on the slider 50, the tab frame 30 completes its role to position the four wires 40, and thus, the four wires 40 are cut off at the top portion of the bonding pads 51 and the tab frame 30 is disconnected from the flexure 21. The slider 50 is rotated in the direction of arrow A shown in FIG. 21(c), and bonded to the suspension tongue 22 of the flexure 21. The four wires 40 connected to the respective bonding pads 51 on the slider 50 are bent downwards in unison with the bonding pads 51 as the slider 50 rotates.
Problems to be Solved by the Invention
In the HDD apparatus, a larger capacity of storage and the speedup of the data access are desired, and the reduction of the distance between a plurality of disks, the increase in the rotational speed of magnetic disks, and the achievement of a higher-density recording are attempted. If the distance between a plurality of disks is shortened, and if the rotational speed of magnetic disks is increased, the velocity of the air flow generated by a rotating disk becomes faster. This air flow causes the head suspension assembly (HSA) to vibrate, thereby reducing reliability for the magnetic head to access data on the magnetic disk. Thus, it needs to decrease the air resistance of the HSA to reduce the vibration of the HSA due to the air flow. To decrease the air resistance of the HSA, it is effective to decrease the area of the side of the HSA exposed to the air flow and decease the width of the HSA in the top side thereof.
However, in the above described conventional HAS, there was a problem that, since an opening window is provided in the top side of the load beam to connect a plurality of wires to the bonding pads on the slider, the width of the HSA in the top side thereof cannot be made small. Further, in the conventional HSA, the margins provided on both side edge portions of the plane portion of the load beam are bent substantially perpendicularly to form a rib. There was a problem that, since this rib has a function of ensuring the rigidity of the HSA while it increases the area receiving the air flow, it causes the HSA to vibrate.
The present invention was made to solve such problems, and its object is to provide a wiring method for HSA in which the width of the HSA in the top side thereof can be further decreased by connecting a plurality of wires to the connecting pads on the slider, without providing any opening window in the top side of the load beam, an assembly stand for HSA, a flexure assembly, a suspension assembly, and a wiring method for the HSA.
The first wiring method for head suspension assembly related to this invention comprises: a first fixing step for fixing a tube on a predetermined location on a suspension assembly, the tube binding a plurality of wires for electrically connecting the magnetic head of a disk storage device and a controller which transmits data between the magnetic head, the suspension assembly having a suspension to which a slider having the magnetic head provided thereon is attached, and a tab frame formed integrally with the suspension, the tab frame being coplanar with the peripheral suspension of the top side of the suspension; a second fixing step for fixing a plurality of wires extending from the fixed tube on predetermined locations on the suspension, while leading the wires to the top side of the suspension; a third fixing step for fixing each wire led to the top side of the suspension on each predetermined location on the tab frame, the third fixing step including a wire bending step for bending each wire led to the top side of the suspension, and leading it to each predetermined location on the tab frame.
Further, the head suspension assembly stand related to this invention is a head suspension assembly stand in which a suspension assembly is attached to a predetermined location for wiring, on the suspension assembly, a plurality of wires for electrically connecting the magnetic head of a disk storage device and a controller which transmits data between the magnetic head, the head suspension assembly stand comprising a plurality of firs pins which each wire led from the rear side to the top side of the suspension assembly is wound around while being fixed on a predetermined location on the suspension assembly, each wound wire being bent in a beveled direction with respect to the longitudinal central axis of the suspension assembly so as to be substantially coplanar with the suspension assembly.
Further, the flexure assembly related to this invention comprising: a flexure partially forming a suspension for elastically supporting a slider, on which the magnetic head of a disk storage device is provided; and a tab frame formed integrally with the flexure so that the tab frame and the peripheral suspension on the top side of the suspension are substantially coplanar, the tab frame having bonding portions to which a plurality of wires are each bonded for electrically connecting the magnetic head and a controller which transmits data between the magnetic head, the tab frame having: a first frame integrally connected to the flexure, the first frame being bendable substantially perpendicularly with respect to the flexure; and a second frame including the bonding portions, integrally connected to the first frame, and a bendable substantially perpendicularly with respect to the first frame, wherein the first frame and the second frame are configured so that, when, at first, the first frame is bent substantially perpendicularly with respect to the tab frame, and then, the second frame is bent substantially perpendicularly with respect to the first frame, the plurality of wires bonded to the bonding portions are positioned at the bondable locations for the respective connecting pads on the slider.
Further, the suspension assembly related to this invention comprises: a suspension for elastically supporting a slider on which the magnetic head of disk storage device is provided; and a tab frame formed integrally with the suspension so that the tab frame and the peripheral suspension of the top side of the suspension are substantially coplanar, the tab frame having bonding portions to which a plurality of wires are each bonded for electrically connecting the magnetic head and a controller which transmits data between the magnetic head, the tab frame having: a first frame integrally connected to the suspension, the first frame being bendable substantially perpendicularly with respect to the suspension; and a second frame including the bonding portions, integrally connected to the first frame, and bendable substantially perpendicularly with respect to the first frame, wherein the first frame and the second frame are configured so that, when, at first, the first frame is bent substantially perpendicularly with respect to the suspension, and then, the second frame is bent substantially perpendicularly with respect to the first frame, the plurality of wires bonded to the bonding portions are positioned at the bondable locations for the respective connecting pads on the slider.
Further, the second wiring method for head suspension assembly comprises: a step for preparing a suspension assembly comprising a suspension for elastically supporting a slider on which the magnetic head of a disk storage device is provided, and a tab frame formed integrally with the suspension so that the tab frame and the peripheral suspension of the top side of the suspension are substantially coplanar, the tab frame having bonding portions to which a plurality of wires are each bonded for electrically connecting the magnetic head and a controller which transmits data between the magnetic head, the tab frame having a first frame integrally connected to the suspension and bendable substantially perpendicularly with respect to the suspension, and a second frame including the bonding portions, integrally connected to the first frame, and bendable substantially perpendicularly with respect to the first frame; a first fixing step for fixing a tube binding the plurality of wires on a predetermined location on the suspension assembly; a second fixing step for fixing the plurality of wires extending from the fixed tube on a predetermined location on the suspension, while leading them to the top side of the suspension, to which the slider on which the magnetic head is provided is attached; a third fixing step for bonding each wire led to the top side of the suspension to the bonding portion of the second frame of the tab frame; an insulation film removing step for removing the insulation film of each connecting portion of the plurality of wires to connect the plurality of wires to the respective connecting pads; a first frame bending step for bending the first frame substantially perpendicularly with respect to the suspension; a second frame bending step for bending the second frame substantially perpendicularly with respect to the first frame, thereby to position the connecting portion of the plurality of wires bonded to the bonding portions of the second frame at the bondable locations for the respective connecting pads on the slider; and an ultrasonic welding step for ultrasonic-welding the respective connecting portions of the plurality of wires to the respective connecting pads on the slider.